During the final year of this grant, I plan to increase enrollment of control infants and those with near-miss SIDS in order to evaluate the development of chemical regulation of ventilation in these two populations. In a subset, I will evaluate the effects of theophylline on demonstrated abnormalities in breathing pattern and regulation. In another subset, I will examine the effects of immunization on the variables being recorded. I will also increase enrollment of parents in order to further examine the hypothesis that abnormality in ventilatory control can be transmitted.